improve location of DNS alt domain docs section

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Jared Kirschner 2021-12-07 15:10:14 -05:00 committed by GitHub
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@ -96,47 +96,6 @@ pairs according to [RFC1464](https://www.ietf.org/rfc/rfc1464.txt).
Alternatively, the TXT record will only include the node's metadata value when the Alternatively, the TXT record will only include the node's metadata value when the
node's metadata key starts with `rfc1035-`. node's metadata key starts with `rfc1035-`.
## Alternative Domain
By default, Consul responds to DNS queries in the `consul` domain,
but you can set a specific domain for responding to DNS queries by configuring the [`domain`](/docs/agent/options#domain) parameter.
In some instances, Consul may need to respond to queries in more than one domain,
such as during a DNS migration or to distinguish between internal and external queries.
Consul versions 1.5.2+ can be configured to respond to DNS queries on an alternative domain
through the [`alt_domain`](/docs/agent/options#alt_domain) agent configuration
option. As of Consul versions 1.11.0+, Consul's DNS response will use the same domain as was used in the query;
in prior versions, the response may use the primary [`domain`](/docs/agent/options#domain) no matter which
domain was used in the query.
In the following example, the `alt_domain` parameter is set to `test-domain`:
```hcl
alt_domain = "test-domain"
```
```shell-session
$ dig @127.0.0.1 -p 8600 consul.service.test-domain SRV
```
The following responses are returned:
```
;; QUESTION SECTION:
;consul.service.test-domain. IN SRV
;; ANSWER SECTION:
consul.service.test-domain. 0 IN SRV 1 1 8300 machine.node.dc1.test-domain.
;; ADDITIONAL SECTION:
machine.node.dc1.test-domain. 0 IN A 127.0.0.1
machine.node.dc1.test-domain. 0 IN TXT "consul-network-segment="
```
-> **PTR queries:** Responses to PTR queries (`<ip>.in-addr.arpa.`) will always use the
[primary domain](/docs/agent/options#domain) (not the alternative domain),
as there is no way for the query to specify a domain.
## Service Lookups ## Service Lookups
A service lookup is used to query for service providers. Service queries support A service lookup is used to query for service providers. Service queries support
@ -319,6 +278,47 @@ without setting the truncate bit. This is to prevent a redundant lookup over
TCP that generates additional load. If the lookup is done over TCP, the results TCP that generates additional load. If the lookup is done over TCP, the results
are not truncated. are not truncated.
## Alternative Domain
By default, Consul responds to DNS queries in the `consul` domain,
but you can set a specific domain for responding to DNS queries by configuring the [`domain`](/docs/agent/options#domain) parameter.
In some instances, Consul may need to respond to queries in more than one domain,
such as during a DNS migration or to distinguish between internal and external queries.
Consul versions 1.5.2+ can be configured to respond to DNS queries on an alternative domain
through the [`alt_domain`](/docs/agent/options#alt_domain) agent configuration
option. As of Consul versions 1.11.0+, Consul's DNS response will use the same domain as was used in the query;
in prior versions, the response may use the primary [`domain`](/docs/agent/options#domain) no matter which
domain was used in the query.
In the following example, the `alt_domain` parameter is set to `test-domain`:
```hcl
alt_domain = "test-domain"
```
```shell-session
$ dig @127.0.0.1 -p 8600 consul.service.test-domain SRV
```
The following responses are returned:
```
;; QUESTION SECTION:
;consul.service.test-domain. IN SRV
;; ANSWER SECTION:
consul.service.test-domain. 0 IN SRV 1 1 8300 machine.node.dc1.test-domain.
;; ADDITIONAL SECTION:
machine.node.dc1.test-domain. 0 IN A 127.0.0.1
machine.node.dc1.test-domain. 0 IN TXT "consul-network-segment="
```
-> **PTR queries:** Responses to PTR queries (`<ip>.in-addr.arpa.`) will always use the
[primary domain](/docs/agent/options#domain) (not the alternative domain),
as there is no way for the query to specify a domain.
## Caching ## Caching
By default, all DNS results served by Consul set a 0 TTL value. This disables By default, all DNS results served by Consul set a 0 TTL value. This disables